JPH05158279A - Electrostatic charge image developing toner - Google Patents

Abstract

PURPOSE:To fix with low energy, to eliminate hot offsets in fixing and to obtain a picture having high fidelity equivalent to that of the initial picture even in continuous use by providing a bridge structure to the surface layer of a resin grain. CONSTITUTION:One or >=2 kinds of vinyl monomers are polymerized, granulated to obtain an electrostatic charge image developing toner consisting of a colored resin grain. A bridge structure is provided to the surface layer of the grain. The resin grain is obtained by suspension polymerization, the grains are stuck, and then a polarity control agent is fed to obtain the toner. This polymer has a thermal characteristic suitable for low-temp. fixing and is polymerized in the presence of a cross-linking agent having >=2 polymerizable double bonds to enhance its offset resistance. Divinylbenzene, divinylnaphthalene, the aromatic divinyl compd. as their derivatives or their mixture are preferably used as the cross-linking agent.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electrostatic charge image developing toner used in electrophotography, electrostatic printing and the like.

[0002]

2. Description of the Related Art Heretofore, toners for developing electrostatic images have used fine powders in which a binder resin made of natural resin or synthetic resin and carbon black or a colorant such as pigment or dye are dispersed. .. The production method is such that a resin medium is melt-kneaded with a toner property imparting agent such as a colorant and a charge control agent, the mixed composition is cooled and then pulverized, and the pulverized product is classified to obtain a toner having a target particle size range. Is generally used. The toner obtained by the above method is widely used because it has excellent dispersibility of carbon black and a polarity control agent. However, the fixing property of the toner obtained by kneading depends on the thermal characteristics of the binder resin used, and in order to obtain a low temperature fixing type toner, it is common to use an acrylic resin or polyester having a low molecular weight. However, in such a case, there is a problem that hot offset occurs. Further, in recent years, a toner having a small particle size is required for improving the image quality of electrophotography, but in order to obtain such a toner, classification is required to be repeated many times according to a kneading method, resulting in poor yield. However, there is a drawback that the manufacturing cost of the toner becomes high.

Therefore, as a method for efficiently producing a toner having a small particle size which does not require a classification step, for example, Japanese Patent Publication No. Sho 38
-10231, 47-51830, 51-14895, JP-A-53-177
As described in Japanese Patent Publication No. 35, No. 53-17736, No. 53-17737, etc., a method by a polymerization method has been proposed. In this method, a composition obtained by adding a water-insoluble monomer, an additive such as a colorant, and a polymerization initiator in an aqueous solution is suspended by high-speed shearing stirring with a homomixer and then polymerized. With this method, a toner with a small particle size can be produced relatively easily, and since it is not necessary to consider the pulverizability, the toner does not become fine powder even if it is used for a long time, so that the life of the developer can be prolonged. The feature is that it is possible to achieve high image quality. However, the toner obtained by the suspension polymerization method has drawbacks such as poor dispersion of a toner property imparting agent such as a colorant and a polarity control agent, and a small particle size but a wide particle size distribution.

In addition to the above, as a method for obtaining a toner having a small particle size, as described in JP-B-57-494 and JP-A-61-13945, core particles containing a pigment and a polarity control agent therein are contained. Although there is a method of forming by using a spray manufacturing method, this method has a drawback that it is very difficult to control the particle size and a classification treatment is required after granulation. As a method for obtaining a toner having a small particle size and a narrow particle size distribution, JP-A-58-106554 and 61-
As disclosed in 18965 and 61-275766, there is a method of producing a so-called core-shell structure toner by adhering or coating a colorant or a toner property-imparting substance on particles having a narrow particle size distribution. The toner produced by this method has a problem in terms of electrical characteristics because the colorant is unevenly distributed on the surface.

As another toner manufacturing method, a method of immersing resin particles in a dye solution and dyeing them has been proposed (Japanese Patent Laid-Open Nos. 50-46333, 1-103631 and 50-46). 154
No. 736, No. 61228458, No. 63-106667, No. 64-90454). This method is a preferable method because it has a small number of manufacturing steps. For example, although the toner obtained by JP-A-61-228458 can obtain a small particle diameter toner having a narrow particle diameter distribution, it is not preferable in terms of low temperature fixing and hot offset generation. It is difficult to control both of them. That is, when the thermal characteristics of the toner for low-temperature fixing are lowered, hot offset tends to occur, and when the resin composition that eliminates the hot offset is used, the problem that low-temperature fixing becomes difficult has not been sufficiently solved. Problems such as dirt and paper jam occur. In addition, when dyeing resin particles obtained by dispersion polymerization, agglomeration of particles occurs, resulting in a significant decrease in yield.

[0006]

SUMMARY OF THE INVENTION The object of the present invention is to fix resin particles prepared in a toner size in a multi-layered manner so that they can be fixed with low energy and can be used continuously without causing hot offset during fixing. Also in the above, it is to provide a toner capable of obtaining an image with high fidelity equivalent to that of the initial image. Another purpose is to dye resin particles,
Another object of the present invention is to provide resin particles for low-temperature fixing, which can be dyed without agglomeration of resin particles.

[0007]

Means for Solving the Problems The inventors of the present invention have conducted extensive studies in order to achieve the above-mentioned object, and as a result, only the composition of the binder resin particles constituting the toner is involved in the low temperature fixing property and the offset property. In addition, the present invention was found to be involved not only in the occurrence of agglomeration of resin particles during dyeing. That is, the toner of the present invention is a toner for developing an electrostatic charge image, which comprises colored resin particles after polymerizing one or more vinyl monomers and granulating, and has a crosslinked structure in the surface layer of the resin particles. It is characterized by

The resin particles used in the toner of the present invention are obtained by a dispersion polymerization method, dyed, and then treated with a polarity control agent to obtain a toner.

In the present invention, the hydrophilic organic liquid used as a diluent for the monomers used during the formation of such resin particles and the reaction of growth of seed particles is, for example, methyl alcohol, ethyl alcohol, denatured ethyl alcohol,
Isopropyl alcohol, n-butyl alcohol, isobutyl alcohol, tert-butyl alcohol, sec
-Butyl alcohol, tert-amyl alcohol, 3
-Pentanol, octyl alcohol, benzyl alcohol, cyclohexanol, furfuryl alcohol, tetrahydrofurfuri alcohol, ethylene glycol,
Alcohols such as glycerin and diethylene glycol,
Examples thereof include ether alcohols such as methyl cellosolve, cellosolve, isopropyl cellosolve, butyl cellosolve, ethylene glycol monomethyl ether, ethylene glycol monoethyl ether, diethylene glycol monomethyl ether and dieethylene glycol monoethyl ether. These organic liquids may be used alone or as a mixture of two or more.

Under the condition that the organic liquids other than alcohols and ether alcohols are used in combination with the above-mentioned alcohols and ether alcohols, the organic liquids are not soluble in the produced polymer particles. Various SP
By changing the value, it is possible to change the polymerization conditions and suppress the size of particles produced, coalescence of seed particles, and generation of new particles. As the organic liquid used in combination with these, hexane, octane, petroleum ether, cyclohexane, benzene, toluene, xylene and other hydrocarbons, carbon tetrachloride, trichloroethylene, tetrabromoethane and other halogenated hydrocarbons, ethyl ether, Dimethyl glycol, trioxane, ethers such as tetrahydrofuran, methylal, acetals such as diethyl acetal, acetone, methyl ethyl ketone, methyl isobutyl ketone, ketones such as cyclohexane, butyl formate,
Acetic acid, ethyl propionate, esters such as cellosolve acetate, acids such as formic acid, acetic acid, propionic acid, etc., nitropropene, nitrobenzene, dimethylamine, monoethanolamine, pyridine, dimethyl sulfoxide, dimethylformamide, etc., sulfur- and nitrogen-containing organic compounds Kind,
In addition, water is included. The above-mentioned inorganic ion is added to the solvent mainly composed of the hydrophilic organic liquid. Alternatively, the polymerization may be carried out in the presence of other inorganic ions. The average particle size, particle size distribution, and drying conditions of the polymer particles produced can be adjusted by changing the type and composition of the mixed solvent at the start of polymerization, during the polymerization, and at the end of the polymerization.

Suitable examples of the dispersion stabilizer during the production of seed particles or the production of grown particles include, for example, acrylic acid, methacrylic acid, α-cyanoacrylic acid, α-cyanomethacrylic acid, itaconic acid, crotonic acid and fumar. Acids, acids such as maleic acid or maleic anhydride, or acrylic monomers containing a hydroxyl group such as β-hydroxyethyl acrylate, β-hydroxyethyl methacrylate, β-hydroxypropyl acrylate, β-hydroxymethacrylate. Propyl, γ-hydroxypropyl acrylate,
Γβ-hydroxypropyl methacrylate, acrylic acid 3
-Chloro-2-hydroxypropyl, methacrylic acid 3-
Chloro-2-hydroxypropyl, diethylene glycol monoacrylic acid ester, diethylene glycol monomethacrylic acid ester, glycerin monoacrylic acid ester, glycerin monomethacrylic acid ester, N-methylol acrylamide, N-methylol methacrylamide, etc., with vinyl alcohol or vinyl alcohol Ethers such as vinyl methyl ether, vinyl ethyl ether, vinyl propiether, etc., or esters of compounds containing vinyl alcohol and a carboxyl group, such as vinyl acetate, vinyl propionate, vinyl butyrate, acrylamide, methacrylamide, diacetone acrylamide. , Or these methylol compounds,
Acrylic chloride, acid chlorides such as methacrylic acid chloride, vinylpyridine, vinylpyrrolidone, vinylimidazole, nitrogen atoms such as ethyleneimine, or homopolymers or copolymers such as those having a multiple ring thereof, polyoxyethylene, Polyoxypropylene,
Polyoxyethylene alkylamine, polyoxypropylene alkylamine, polyoxyethylene alkylamide, polyoxypropylene alkylamide, polyoxyethylene nonylphenyl ether, polyoxyethylene lauriphenyl ether, polyoxyethylene stearyl phenyl ether, polyoxyethylene nonylphenyl Polyoxyethylenes such as ethers, celluloses such as methylcellulose, hydroxyethylcellulose, hydroxypropylcellulose, or those having the above-mentioned hydrophilic monomer and a benzene nucleus such as styrene, α-methylstyrene, vinyltoluene or a derivative thereof or acrylonitrile or methacryl Copolymers with acrylic acid or methacrylic acid derivatives such as ronitrile and acrylamide, and crosslinkability Nomar such as ethylene glycol dimethacrylate, diethylene glycol dimethacrylate, allyl methacrylate, a copolymer of divinylbenzene can be used.

These polymer compound dispersants may be appropriately selected depending on the hydrophilic organic liquid used, the seeds of the intended polymer particles and the production of seed particles depending on the production of growing particles.
In particular, a polymer having a high affinity for the polymer particle surface and an adsorptive property and a high affinity for a hydrophilic organic liquid and a high solubility is selected in order to prevent the polymer particles from uniting mainly in three dimensions. Further, in order to increase the repulsion between the particles in a three-dimensional manner, those having a certain molecular weight, preferably those having a molecular weight of 10,000 or more are selected. However, when the molecular weight is too high, the viscosity of the liquid is remarkably increased, the operability and the stirring property are deteriorated, and the precipitation establishment of the produced polymer varies on the particle surface. It is also effective for stabilization that a part of the above-mentioned polymer compound dispersant monomer is allowed to coexist with the monomer constituting the desired polymer particles.

Further, in combination with these polymer compound dispersants, cobalt iron, nickel, aluminum, copper, tin,
Metals such as lead and magnesium or their alloys (especially 1 μm
The following particle sizes are preferable), and inorganic compound fine powders of oxides such as iron oxide, copper oxide, nickel oxide, zinc oxide, titanium oxide, and silicon oxide, higher alcohol sulfate ester salts,
Anionic surfactants such as alkylbenzene sulfonate, α-olefin sulfonate, and phosphoric acid ester, alkylamine salt, aminoalcohol fatty acid derivative, polyamine fatty acid derivative, amine salt type such as imidazoline, alkyltrimethylammonium salt, dialkyl Quaternary ammonium salt type cationic surfactants such as dimethylammonium salt, alkyldimethylbenzylammonium salt, pyridinium salt, alkylisoquinolinium salt and benzethonium chloride, nonionic surface active agents such as fatty acid amide derivatives and polyhydric alcohol derivatives Agent, for example, the stability and particle size of the produced polymer particles, even if an amphoteric surfactant of amino acid type such as alanine type [eg, dodecyldi (aminoethyl) glycine, di (octylaminoethyl) glycine] or betaine type is used together. Diameter distribution It can be further enhanced improvements.

Generally, the amount of the polymer stabilizer used in the production of the seed particles varies depending on the kind of the polymerizable monomer for forming the intended polymer particles, but is based on the hydrophilic organic liquid. 0.1-
It is preferably 15% by weight, more preferably 1 to 5% by weight. When the concentration of the polymer dispersion stabilizer is low, the polymer particles produced have a relatively large particle size, and when the concentration is high, a small particle size is obtained, but more than 15 wt%. Even if used, it has little effect on reducing the particle size. Needless to say, the above-mentioned polymer dispersion stabilizer and, if necessary, the inorganic fine powder, pigment, and surfactant are necessary for the production of seed particles, but they are not required for coalescence of particles during the growth reaction. The polymerization may be carried out by allowing it to be present in a vinyl monomer solution or seed particle dispersion liquid added for the purpose of preventing the above. The particles initially formed are stabilized by the polymer dispersion stabilizer distributed in equilibrium between the hydrophilic organic liquid and the polymer particle surface, but the unreacted vinyl monomer remains in the hydrophilic organic liquid. When present in a considerable amount, it has a somewhat swollen stickiness and overcomes the steric repulsive force of the polymer dispersion stabilizer to agglomerate. Further, when the amount of the monomer is extremely large with respect to the hydrophilic organic liquid, the produced polymer is completely dissolved and does not precipitate unless the polymerization proceeds to some extent. The state of precipitation in this case takes the form of forming a highly sticky lump. Therefore, the amount of the monomer with respect to the hydrophilic organic liquid at the time of producing the particles is naturally limited, and the amount of the monomer / hydrophilic organic liquid is about 1 although it is slightly different depending on the kind of the hydrophilic organic liquid. Below, preferably below 0.7 is suitable.

In the present invention, the monomer is one that is soluble in a hydrophilic organic liquid, and is, for example, styrene, 0-methylstyrene, m-methylstyrene, p-methylstyrene, α-
Methyl styrene, p-ethyl styrene, 2.4-dimethyl styrene, pn-butyl styrene, p-tert-butyl styrene, p
Styrenes such as -n-hexylstyrene, pn-octylstyrene, pn-nonylstyrene, pn-decylstyrene, pn-dodecylstyrene, p-methoxystyrene, p-phenylstyrene, p-chlorostyrene, 3.4-dichlorostyrene , Methyl acrylate, ethyl acrylate, butyl acrylate, isobutyl acrylate, propyl acrylate,
Acrylic acid-n-octyl, dodecyl acrylate, lauryl acrylate, 2-ethylhexyl acrylate, stearyl acrylate, 2-chloroethyl acrylate, phenyl acrylate, α-chloromethyl acrylate, methyl methacrylate, methacrylic acid Ethyl, propyl methacrylate, n-butyl methacrylate, isobutyl methacrylate, n-octyl methacrylate, dodecyl methacrylate, lauryl methacrylate, 2-ethylhexyl methacrylate, stearyl methacrylate, phenyl methacrylate, dimethyl methacrylate Α-Methyl fatty acid monocarboxylic acid esters such as aminoethyl and diethylaminoethyl methacrylate, acrylic acid or methacrylic acid derivatives such as acrylonitrile, methacrylonitrile and acrylamide, vinyl chloride Vinylidene chloride, vinyl bromide, means a mixture with one another with a mixture of single or cross made of vinyl halides and monomers capable of copolymerizable therewith, such as vinyl fluoride.

The polymerization conditions of the particles are determined by the target average particle size of the polymer particles and the concentration and blending ratio of the polymer dispersant and vinyl monomer in the hydrophilic organic liquid according to the target particle size distribution. Generally, if the average particle size of the particles is to be reduced, the concentration of the polymer dispersant is set high, and if the average particle size is to be increased, the concentration of the polymer dispersant is set low. On the other hand, if the particle size distribution is to be made extremely sharp, the vinyl monomer concentration is set low, and if the particle size distribution is relatively wide, the vinyl monomer concentration is set high.

The particles are prepared by completely dissolving the polymer dispersion stabilizer in the hydrophilic organic liquid, and then using one or more vinyl monomers, a polymerization initiator, and other inorganic fine powders and surface active agents if necessary. 30-300 by adding agents, dyes, pigments, etc.
The initiator used under normal stirring of rpm, preferably at the lowest speed, while using a stirring blade of a turbine type rather than a paddle type while stirring at a speed such that the flow in the tank becomes uniform. Polymerization is carried out by heating at a temperature corresponding to the decomposition rate of. Since the temperature at the initial stage of polymerization has a large influence on the particle size to be generated, it is desirable to raise the temperature to the polymerization temperature after adding the monomer, and dissolve the initiator in a small amount of solvent and add it.

At the time of polymerization, it is necessary to sufficiently expel oxygen in the air in the reaction vessel with an inert gas such as nitrogen gas or argon gas. If the oxygen barge is insufficient, fine particles are likely to be generated. To carry out the polymerization in a high polymerization rate range,
A polymerization time of 40 hours is required, but the polymerization rate can be controlled by stopping the polymerization in a desired particle size and particle size distribution state, adding a polymerization initiator in sequence, and performing the reaction under high pressure. You can speed it up. After completion of the polymerization, it may be used as it is in the dyeing step, or after removing unnecessary fine particles, residual monomer, polymer dispersion stabilizer, etc. by operations such as sedimentation separation, centrifugation, decantation, etc., polymer slurry However, if the dispersion stabilizer is not removed, the stability of the dyeing system is higher and unnecessary aggregation is suppressed.

Further, the polymer in the present invention has thermal characteristics suitable for low temperature fixing, and since the offset resistance is enhanced,
Polymerization is performed in the presence of a so-called cross-linking agent having two or more polymerizable double bonds. As a crosslinking agent preferably used,
Aromatic divinyl compounds that are divinylbenzene, divinylnaphthalene and their derivatives, other ethylene glycol dimethacrylate, diethylene glycol methacrylate, triethylene glycol methacrylate, trimethylolpropane triacrylate, allyl methacrylate, tert-butylaminoethyl methacrylate,
All divinyl compounds such as tetraethylene glycol methacrylate, diethylenic carboxylic acid ester such as 1,3-butanediol dimethacrylate, N, N-divinylaniline, divinyl ether, divinyl sulfide, divinyl sulfone and 3 or more vinyl groups The compounds are used alone or as a mixture. When the growth polymerization reaction is subsequently carried out using the seed particles thus crosslinked, the inside of the growing polymer particles is crosslinked. On the other hand, when the vinyl monomer solution used for the growth reaction contains the above-mentioned cross-linking agent, a polymer whose particle surface is hardened is obtained.

Dyeing in the present invention is as follows. That is, the resin particles A are dispersed in an organic solvent which does not dissolve the resin particles A, and before or after the dye is dissolved in the solvent, after the dye is penetrated into the resin particles A and colored, In the method for producing a dyed toner by removing the organic solvent, as a dye, the relationship between the solubility [D ₁ ] of the dye in the organic solvent and the solubility [D ₂ ] of the dye in the resin of the resin particles A is [D ₂ ]. ,
A dye in which [D ₁ ] / [D ₂ ] ≦ 0.5 is selectively used, whereby a toner in which the dye has penetrated (diffused) to the deep part of the resin particle A can be efficiently produced. Is.

In this method, it is preferable to disperse the resin particles in an organic solvent in which a dye is dissolved, then keep the liquid temperature below the glass transition temperature of the resin particles and stir. The stirring method may be carried out using a commercially available stirrer, such as a homomixer or a magnetic stirrer. Further, the slurry obtained at the end of the polymerization by dispersion polymerization or the like, that is, the dispersion liquid in which the polymerized resin particles are dispersed in the organic solvent, may be directly added with the dye and heated and stirred under the above conditions. ..
If the heating temperature exceeds the glass transition temperature, fusion of the resin particles will occur.

In addition, the dyed colored resin particles are plasticized by the dye molecules spreading the crystal parts of the particles. Therefore, the resin particles may partially aggregate even when dyed at a temperature below the glass transition temperature. A desirable resin particle constitution for preventing agglomeration during dyeing is that the resin particle surface layer is crosslinked.

As the dye used for dyeing, the ratio [D ₁ ] / [D ₂ ] of the solubility of the dye to the resin constituting the resin particles based on the solubility [D ₁ ] of the dye in the organic solvent used Should be 0.5 or less. Furthermore, [D ₁ ] / [D ₂ ]
Is preferably 0.2 or less. The dye is not particularly limited as long as it satisfies the above-mentioned solubility characteristics, but water-soluble dyes such as cationic dyes and anion dyes may have large environmental fluctuations, and the resistance of the toner becomes low, resulting in a low transfer rate. Therefore, vat dyes, disperse dyes and oil-soluble dyes are preferably used, and oil-soluble dyes are particularly preferable.

Further, several kinds of dyes can be used in combination depending on the desired color tone. The ratio (weight) of the dye to be dyed and the resin particles is arbitrarily selected according to the degree of coloring, but is usually used in a ratio of 1 to 50 parts by weight of dye to 100 parts by weight of resin particles. Is preferred. For example, when alcohols such as methanol and ethanol having a high SP value are used as the dyeing solvent and a styrene-acrylic resin having an SP value of about 9 is used as the resin particles, dyes that can be used include, for example, Dyes such as. CI SOLVENT YELLOW (6,9,17,31,35,100,102,103,105) CI SOLVENT orange (2,7,13,14,66) CI SOLVENT RED (5,16,17,18,19,22,23,143,145,146,1
49,150,151,157,158) CI SOLVENT VIOLET (31,32,33,37) CI SOLVENT BLUE (22,63,78,83 ~ 86,91,94,95,104) CI SOLVENT GREEN (24,25) CI SOLVENT BROWN (3,9) etc.

Among commercially available dyes, for example, Aizen SOT dyes from Hodogaya Chemical Co., Yellow-1,3,4, Orange-1,2,3, Scarlet-
1, Red-1,2,3, Brown-2, Blue-1,2, Violet-1, Green-
1,2,3, Black-1,4,6,8 and BASF sudan dye, Yellow-14
0,150, Orange-220, Red-290,380,460, Blue-670, Mitsubishi Kasei's dialresin, Yellow-3G, F, H2G, HG, HC, HL, Or
ange-HS, G, Red-GG, S, HS, A, K, H5B, Violet-D, Blue-J,
G, N, K, P, H3G, 4G, Green-C, Brown-A and Orient Chemistry
Oil color from Yellow-3G, GG-S, # 105, Orange-P
S, PR ,, # 201, Scarlet- # 308, Red-5B, Brown-GR, # 416, G
reen-BG, # 502, Blue-BOS, HN, Black-HBB, # 803, EE, EX,
Sumiplast, Bull-GP, OR, Red F from Sumitomo Chemical Co., Ltd.
B, 3B, Yellow FL7G, GC, Nippon Kayaku's Kayaron, Polyester Black EX-SH300, Kayaset Red-B Blue A
-2R etc. can be used. Of course, the dye is not limited to the above examples because it is appropriately selected depending on the combination of the resin particles and the solvent used at the time of dyeing.

As the organic solvent used for dyeing the resin particles with the dye, those which do not dissolve the resin particles used or those which cause some swelling, specifically, the difference from the solubility parameter (SP value) Is 1.0 or more, preferably 2.0 or more. For example, for styrene-acrylic resin particles, an alcohol type such as methanol, ethanol and n-propanol having a high (SP value) or n-hexane or n-heptane having a low (SP value) is used. Of course, if the difference in (SP value) is too large, the wetting of the resin particles becomes poor and good dispersion of the resin particles cannot be obtained. Therefore, the optimum (SP value) difference is preferably 2 to 5.

Next, the production of resin particles and the dyeing of resin particles in the present invention will be described with reference to experimental examples. (Preliminary experiment) The following materials were placed in a reactor that can be sealed and rotated in a constant temperature water bath. Methanol 100 parts by weight Styrene-maleic anhydride copolymer 5 parts by weight A container was gently stirred in a 60 ° C warm bath and the styrene-maleic anhydride copolymer as a dispersion stabilizer was completely dissolved in about 2 hours. ..

Methanol solution in which the above dispersion stabilizer is dissolved
250 parts by weight were transferred into a sealable reaction container which rotated in a constant temperature water bath, and then the following composition was added. Styrene 65 parts by weight Methyl acrylate 35 parts by weight Dodecyl mercaptan 0.5 parts by weight 1,3-butanediol dimethacrylate 0.5 parts by weight While mixing by rotating the container, N ₂ gas is blown into the container to completely remove air. Kick out,
The container was closed. Then, the water tank was kept at 60 degrees, and the polymerization was carried out while stirring at 100 rpm. At this time, 2.0 parts by weight of 2,2-azobisisobutyronitrile was used as an initiator to start the polymerization, and the polymerization was completed in 24 hours. The relationship between the polymerization time and the polymerization rate at this time is shown in FIG.

Experimental Example 1 A methanol solution 250 in which the dispersion stabilizer prepared above was dissolved.
A part by weight was transferred into a sealable reaction container which rotates in a constant temperature water tank, and the following materials were charged. Styrene 65 parts by weight Methyl acrylate 35 parts by weight Dodecyl mercaptan 0.5 parts by weight 1,3-butanediol dimethacrylate 0.5 parts by weight While mixing by rotating the container, N ₂ gas is blown into the container to completely blow air. Drive out,
The container was closed. Thereafter, the water tank was kept at 60 degrees, and polymerization was carried out while stirring at 100 rpm. At this time, as an initiator
Polymerization was initiated using 2.0 parts by weight of 2,2'-azobisisobutyronitrile. Three hours after the initiation of polymerization, 1.0 part by weight of dodecyl mercaptan was diluted to 30 parts by weight of methanol and added to the polymerization system in about 30 minutes. The polymerization rate when dodecyl mercaptan was added was 24% as a result of measurement by gas chromatography by the internal standard method. 10 hours after the start of polymerization 1.
0 part by weight of 1,3-butanediol dimethacrylate (crosslinking agent) was diluted to 30 parts by weight of methanol and added to the polymerization system in about 30 minutes. The polymerization rate when 1,3-butanediol dimethacrylate was added was 63% as a result of measurement by gas chromatography by the internal standard method. The polymerization was further continued and completed in 24 hours. The polymerization rate at the end of the polymerization was 95.4% as measured by gas chromatography according to the internal standard method. 20 by Coulter Multisizer
In the particle size distribution measurement using a μm aperture tube, the volume average diameter is 4.920 μm and the number average diameter is 4.
The ratio was 920 μm and 1.02. This polymer is a resin particle N
Set to O.1.

Experimental Examples 2 to 4 14 hours, 18 hours and 24 hours after the initiation of the polymerization under the same charged formulation, 1.0 part by weight of 1,3-butanediol dimethacrylate was diluted to 30 parts by weight of methanol to give 30 parts. About minutes, the particles were added to the polymerization system to prepare particles. These polymers are referred to as resin particles NO.2, NO.3 and NO.4.

Coloring of Resin Particles 30.0 parts by weight of Oil Black 860 was added to 20 parts by weight of methanol, heated and dissolved at 50 ° C., cooled to room temperature, and filtered to obtain 10 parts by weight of a filtrate with a 1 μm microfilter. Resin particles N were added to 100 parts by weight of each filtrate thus prepared.
40 parts by weight of each of O.1 to 4 was added, and the mixture was stirred at room temperature for 2 hours,
After that, the dispersion is spun down and the supernatant is removed.
The operation of redispersing in a mixed solvent of 50 parts by weight of water and 50 parts by weight of water was repeated three times. After separation by filtration, air-drying, and drying under reduced pressure at 40 ° C. for 6 hours to obtain resin particles colored with oil black 860. This particle was cut by the frozen ultra-thin section method and its cross section was SEM
As a result of observation in the photograph, it was confirmed that the surface layer portion of the particles was dyed only as the addition time of the crosslinking agent was delayed. Since the reaction speed of the cross-linking agent is high, the polymerization field becomes the particle surface layer,
This is probably because the morphologies of the polymer inside the particle and the surface layer are different.

Dia Resin instead of Oil Black 860
The same operation was performed on the resin particles No. 1 to 4 using Yellow, and the dyeing condition was observed by the frozen ultra-thin section method.As with the case of Oil Black 860, the slower the addition time of the cross-linking agent, the more dyed the surface layer. It was confirmed that not. From these, it can be seen that the surface layer of the particles forms a crosslinked structure by further adding the crosslinking agent after the polymerization rate of the polymerization system becomes 60% or more.

[0033]

EXAMPLES The present invention will be described in more detail with reference to Examples and Comparative Examples. Examples 1 to 4 100 parts by weight of the resin particles 1 to 4 prepared above were dispersed in methanol (slurry state), and 1.2 g of Dia Resin Yellow 3G (manufactured by Mitsubishi Chemical Corporation) was stirred with a spatula for about 10 minutes. Then, the resin particles were dyed by stirring at 50 ° C. for 3 hours. After that, the dispersion liquid is cooled to room temperature, and the supernatant liquid is removed by centrifugal sedimentation to remove methanol.
3 operation of redispersion in a mixed solvent of 50 parts by weight and 50 parts by weight of water
The particles were washed once to wash. After separation by filtration, air-drying, and drying under reduced pressure at 40 ° C. for 6 hours to obtain each toner of Examples 1 to 4 colored with Dia Resin Yellow 3G. Each of the toners was coated with a silicone compound in which a charge control agent was dissolved on the surface of ferrite, and then mixed with a carrier subjected to high temperature treatment to prepare a developer.

These developers were put in a Ricoh copying machine FT-5510 and image evaluation was performed. The resolution of the obtained image is 7.1 lines /
The image was not deteriorated even after running for 30,000 mm or more and 30,000 sheets, and a clear image was retained as it was at the initial stage. Further, these image samples were sandwiched between vinyl mats and allowed to stand in an environment of 50 ° C. for one week, but the toner was not fused to the vinyl mats.

Examples 5 to 8 Examples 1 to 4 are Dia Resin Yellow 3G and Ton MAGENNTA10.
Magenta toners of Examples 5 to 8 were obtained by performing the same operation except that the number was changed to 1 (manufactured by Mitsui Toatsu Co., Ltd.). Each toner was coated on the surface of ferrite with a silicon compound in which a charge control agent was dissolved, and then mixed with a carrier subjected to high temperature treatment to prepare a developer, and an image was evaluated. The result was good.

Examples 9 to 12 Examples 1 to 8 are Dia Resin Yellow 3G or Ton MAGENT
The cyan toners of Examples 9 to 12 were obtained by performing the same operation except that A101 was changed to SOT BLUE2. Each toner was coated on the surface of ferrite with a silicone compound in which a charge control agent was dissolved, and then mixed with a high-temperature-treated carrier to prepare a developer, and image evaluation was performed. The result was good.

Comparative Example 1 In the above-mentioned Experimental Example 1, the cross-linking agent was added from the start of polymerization to 4
Resin particles No. 5 were prepared in the same manner except that they were changed after the elapse of time. The polymerization rate when the crosslinking agent was added was 31%. Then, in the same manner as in Experimental Examples 2 to 4, resin particles
NO.5 was colored. When these particles were cut by the frozen ultra-thin section method and their cross sections were observed by SEM photographs, they were found to be uniformly dyed even inside the particles, although the degree of coloring was very weak. This is probably because the morphologies of the polymers forming the particles are almost the same. Next, the resin particles No. 5 were treated in the same manner as in Examples 1 to 4 to obtain colored toner of Comparative Example 1. This toner was coated on the surface of ferrite with a silicone compound in which a charge control agent was dissolved, and then mixed with a carrier subjected to high temperature treatment to prepare a developer. Next, this developer was put into a Ricoh copier FT-5510 and image evaluation was performed. As a result, offset was seen in the image sample, and paper jams frequently occurred.

Comparative Examples 2 to 5 In the case of Comparative Example 1, the cross-linking agent was added at 5 times from the initiation of polymerization.
Resin particles No. 6 were prepared in the same manner except that they were changed after the elapse of time. The polymerization rate when the crosslinking agent was added was 38%. Similarly, the cross-linking agent was added after 6 hours, 7 hours and 8 hours to obtain resin particles NO. 7, 8 and 9. Then, the resin particles No. 6 to 9 were colored in the same manner as in Comparative Example 1.
These particles were cut by the frozen ultra-thin section method and their cross section was SE-cut.
As a result of observation on the M photograph, the degree of coloring was very weak, but the inside of the particles were uniformly colored. Next, resin particles NO.6
To 9 were treated in the same manner as in Comparative Example 1 to obtain colored toners of Comparative Examples 2 to 5. Each of the toners was coated with a silicone compound in which a charge control agent was dissolved on the surface of ferrite, and then mixed with a carrier subjected to high temperature treatment to prepare a developer. These developers were put into a Ricoh copier FT-5510 and image evaluation was performed. As a result, offset was seen in the image sample, and paper jams frequently occurred.

[0039]

As described above, by forming the surface layer of the resin particles in a crosslinked structure, a toner is obtained in which the resin particles do not aggregate during dyeing, and offset and paper jam do not occur despite low temperature fixing. Be done.

[Brief description of drawings]

FIG. 1 is a diagram showing the relationship between polymerization time and polymerization rate.

Claims (2)

[Claims] 1. A toner for developing an electrostatic charge image comprising colored resin particles after polymerizing one or more vinyl monomers and granulating, wherein the surface layer of the resin particles has a crosslinked structure. Characteristic electrostatic toner image developing toner. 2. The toner for developing an electrostatic charge image according to claim 1, wherein the resin particles having the crosslinked structure are dyed.